1. Field of Invention
This invention relates to improvements in and relating to members, in particular but not exclusively members for use in devices for metering (measuring) the mass flow ("bulk flow") of so-called bulk material. The invention also relates to members for use in impellers and propellers, and to methods of obtaining such members.
2. Background of Prior Art
An example of the mass flow of bulk material is the flow of grain to the grain tank in a combine harvester. Members in accordance with the invention are particularly suitable for use in flow meters that operate by measuring forces of this flow on a sensor surface. Surfaces in accordance with the invention may also be employed in hoppers, silos, harvesting and cutting machinery other than combine harvesters, conveying machinery and various kinds of manufacturing and medical apparatuses.
Bulk flow may also embrace, e.g. the flow of bulk grain and chemicals in transport vehicles (such as tankers, ships and railway tanker wagons); the flow of powders, and materials of larger particle size such as fruit, vegetables, coal, minerals and ores; and even the flow of liquids of high viscosity. Thus the invention may be of use in the measuring of characteristics of bulk flow in liquids whose viscosity changes. In general terms, bulk flow of material may in this context be regarded as any flow of matter in contact with a surface, in which the effects of friction between the surface and the material usually influence the maximum flow rate, and in which the matter exhibits free flow behaviour. Those skilled in the art will know that various factors, such as the tendency of grains of bulk material to cohere and to adhere to the surface; and the effects of friction between individual grains, also influence the mass flow rate of bulk materials. However, the effects of such factors are small compared with the effects of friction between the bulk material and the surface along which it travels.